323589993-Experiment-2-Lab-Report.docx
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ADAMSON UNIVERSITY College of Engineering
C hem hemi cal cal E ngi ng i nee neer i ng D epar tme tment M a n i l a
Experiment no. 2
STEAM DISTILLATION
Submitted by:
Lavilles, Francis Dominic Lee Gee Hyun Lojica, Kathlyn Joyce M.
Date performed: July 18, 2015 Date submitted: July 27, 2015
ABSTRACT:
Steam distillation is an important method of separating immiscible liquids. This experiment aims to observe a steam distillation process. In order to observe the steam distillation process, toluene-water system was used in the study. A simple steam distillation set up was used in the experiment. The distillation was made and the temperature was recorded when the total volume of the distillate in the receiver has reached certain corresponding amounts. The results showed that as the temperature increases, the pressure also increases for toluene, water and mixture. The value of the pressure for the mixture was between the values of the pressure of toluene and water. The pressure versus temperature or toluene water and the mixture was plotted. Near accurate results of the temperature at each volume of the distillate was obtained. The steam distillation process was observed comprehensively in this experiment.
INTRODUCTION:
Immiscible liquids are liquids that do not mix to give a single phase. When two immiscible liquids are boiled, they will boil at temperature lower than the boiling point of either of the pure liquids. Steam distillation is a useful process of separating immiscible liquids. In this process, a liquid which is immiscible with water is distilled using steam. Steam distillation works on the principle that in a mixture, there is a point where two liquids become immiscible. In this mixture system, the total vapor pressure deviates from Raoult's Law prediction. Adding the vapor pressure of two liquids comprising the binary mixture system will result to vapor pressure of the system. The mole fraction of each liquid in the binary system will not affect the vapor pressure. Also at the boiling point of the mixture, dividing the partial pressures of the compound in the vapor will result to the ratio of the vapor pressures of the pure liquids. In this experiment, steam distillation of the toluene - water system was done. The study aims to examine the steam distillation process of the toluene - water system. = = = = = >> °
°
=
° °
REVIEW OF RELATED LITERATURE:
Substances with different volatilities can be separated by distillation. The process of distillation was first developed by Jabir ibn Hayyan. In modern times, distillations are widely applied in labortory scale, industial distillaton, distillation of herbs for perfumery and medicinals, and food processing. Steam distillation is used for compounds that are heat sensitive. Steam is bubbled through a heated mixture of the raw material. The vaporization of the target substance can be described by using Raoult's Law. Steam distillation has many applications. In a recent study, steam distillation is used to obtain laurel extract (Zekovic, et. al.). In another study, the steam distillation of essential oils from Lemon Grass was examined (Amenaghawon, 2014). Steam distillation of essential oils was also investigated in other studies (Mulvaney, et. al.). Another study probe the extraction of essential oil from Cinnamon (Cinnamomum zeylanicum). The influence on the quality of essential lemon oil by distillation process is determined by a recent study (Gamarra, et. al.) There are also advance ways of performing the distillation of mixtures like benzene and toluene.(Phiyanalinmat, 2015). Some advance methods use algorithms to determine the optimum reflux ratio (Abolpour and Mohebbi, 2014) In mixtures that involve more than two components, more complicated processes are needed in detection and separation of substances. A complex sample of benzene, toluene, ethylbenzene and xylene requires a hybrid separation and detection device for analysis as examined in recent researches (Iglesias et. al. , 2009). When benzene and toulene mix with other comopund like xylene, the concentrations are dtermined using advance process such as High Performance Liquid Chromatography-UV detection (HPLC-UV) (Bahrami, et. al.) Process simulation has been applied in a recent study to design the benzene-toluene distillation (Phiyanalinmat, 2015). Another study presented modeling and simulation of a benzene recovery process by extractive distillation (Brondani, et. al., 2015)
METHODOLOGY:
A steam distillation set-up was prepared. Eighty milliliters of toluene was placed in the round bottom flask and water was filled in the distilling flask up to half of the flask. The distilling flask was heated until the water boiled. When it started to boil, the flame has been lowered just enough to continue the boiling. The first distillate (2-3mL) was disposed. The temperature was recorded and the receiver was placed back under the adapter. The distillation and recording of temperature was continued until the distillate in the receiver was 2.5ml, 5ml, 7.5ml, 10ml, 12.5ml, 15ml, 17.5ml, 20ml, 22.5ml, 25ml. Distillation was stopped when the collected distillate had reached 25ml. The distillates were cooled and were left to separate fully. Each of the distillate were transferred in the graduated cylinder to measure the volume of water and toluene. The data for vapor pressure of toluene and water in different temperatures (40c,50c,60c,70c,80c,90c) was obtained from the handbook. The vapor pressures of the mixture at those temperatures are computed. The vapor pressures of toluene-water and the mixture was plotted. The theoretical boiling point of the mixture was determined from the plot. The theoretical composition of the distillate was also obtained from the plot.
RESULTS AND DISCUSSION:
The pressure v.s temperature graph of toluene and water mixture was made after applying Raoult's Law to the mixture. As the temperature increases, the pressure also increases for toluene, water and mixture. The values of the pressure for the mixture were between the values of the pressure of toluene and water. The use of steam distillation in extracting inorganic liquids has many advantages. In the steam distillation process, the water vapor transfer small amounts of the vaporized substance to the condensation flask where the separation of condensed liquids occurs. This allows easy collection. Normal distillation of inorganic liquids will require high temperature. Some of these molecules will be broken up by heating at high temperature. Using steam distillation avoids this because the required temperature is low.
It is not possible to carry out steam distillation at 100 c because the boiling point of the water is 100 degree celcius so the water will boil if the temperature exceeds 100 degree celcius. In steam distillation, the pressure of the two components must add up to 1atm.
Table 1: Temperature and vapour pressure of water, toluene, and the mixture. Temperature (℃)
Vapor Pressure of Vapor Pressure of Vapor Pressure of Toluene
Pressure
Mixture
40
59.16
55.33
55.89
50
92.11
92.58
92.51
60
138.96
149.44
147.92
70
203.75
233.89
229.51
80
291.22
355.78
346.40
90
406.74
527.42
509.89
Table 2: Volume and boiling point of Distillate Volume
2.5
5
7.5
10
12.5
15
17.5
20
22.5
25
36
34
34
34
34
34
33
34
-
(ml) Temperature 36 (℃)
Table 3: Volume, mole fraction and volume percent of the mixture Volume
of Volume
of Volume
of Mole of H2O
Mole
Mixture
water
Toluene
2.5
0.2
2.8
0.011
0.0019
5
0.8
4.2
0.044
0.0076
7.5
1.5
6
0.083
0.014
10
1.8
8.2
0.1
0.017
12.5
3.8
11.2
0.21
0.036
15
5.6
9.4
0.31
0.053
17.5
10
7.5
0.56
0.094
20
17.4
2.6
0.97
0.16
22.5
22.5
0
1.25
0.2
25
-
-
-
-
Volume
of Mole
Mixture
of
of toluene
fraction Mole fraction of Volume % Toluene H2O
Volume %
Of
Of
H2O
Toluene
2.5
0.85
0.15
8
92
5
0.85
0.15
16
84
7.5
0.85
0.15
20
80
10
0.85
0.15
18
82
12.5
0.85
0.15
25.33
74.67
15
0.85
0.15
37.33
62.67
17.5
0.85
0.15
57.14
42.86
20
0.85
0.15
87
13
22.5
0.85
0.15
100
0
25
-
-
-
-
P vs T graph 600 500 400 e r u s s 300 e r p
toluene water
200
mixture
100 0 0
20
40
60
80
100
Temperature
Fig.1 Pressure v.s. Temperature of Toluene, Water and Mixture
CONCLUSIONS AND RECOMMENDATION:
In the conduct of experiment, the process of steam distillation was observed. The steam distillation of the binary system of toluene and water was examined. A plot of pressure versus temperature for toluene, water and the mixture was made and was studied. The researchers recommended that careful measures must be taken so that there will be no leakage during the distillation process. This must be done in order to get better results.
REFERENCES:
1. Zekovic Z.P., Lepojevic Z.D., Mujic I.O., 2009, Laurel Extracts Obtained by Steam Distillation, Supercritical Fluid and Solvent Extraction. Journal of Natural Products. Vol. 2, pp 104-109 2. Amenaghawon N.A., Okhueleigbe K.E., Ogbeide S.E., and Okieimen C.O. 2014. Modelling the Kinetics of Steam Distillation of Essential Oils from Lemon Grass (Cymbopogon Spp.)International Journal of Applied Science and Engineering 2014. 12,2: pp 107-115 3. Iglesias R.A., TsowF ., Wang R., Forzani E.S., Tao N,. 2009 Hybrid Separation and Detection Device for Analysis of Benzene, Toluene, Ethylbenzene, and Xylenes in Complex Samples. Journal of Analytical Chemistry, 2009, 81 (21 ), pp 8930 – 8935 4. Abolpour B., Mohebbi A,. 2014. Optimization of the reflux ratio of benzene-toluene stage distillation columns by the Cuckoo algorithm. Petroleum Science, 2014, Vol. 11, Issue 3, pp 446-453 5. Mulvaney J., 2012. Essential Oils and Steam Distillation. Journal of the New Zealand Association of Medical Herbalists 2012 6. Wong Y.C., Ahmad-Mudzaqqir M.Y., and Wan-nurdiyana W.A., 2014. Extraction of Essential Oil from Cinnamon (Cinnamon zeylanicum). Oriental Journal of Chemistry, 2014, Vol. 30, No. 1 7. Gamarra F.M.C, Sakanaka L.S., Tambourgi E.B., Cabral F.A., 2006. Influence on the Quality of Essential Lemon (Citrus aurantifolia) oil by Distillation Process. Brazilian Journal of Chemical Engineering, 2006, Vol 32, No. 01, pp 283-291 8. Bahrami A., Mahjub H., Sadeghian M., Golbabaei F., 2011. Determination of Benzene, Toluene and Xylene (BTX) Concentrations in Air Using HPLC Developed Method Compared to Gas Chromatography.International Journal of Occupational Hygiene 2011
9. Phiyanalinmat S., 2015. Design of Benzene-Toluene Distillation for the Minimum Energy Consumption by Chemical Process Simulation. Department of Inustrial Chemistry, Faculty of Science, Thailand. 17th Regional Symposium on chemical Engieering. 10. Brondani L.B., Flores G.B., Soares R.P., 2015. Modeling and Simulation of a Benzene Recovery Process by Extractive Distillation. Brazilian Journal of Chemical Engineering, 2015, Vol. 32, No. 01, pp. 283 - 291
APPENDIX:
Vapor Pressure for Toluene
log (P) = 6.95464 −
1344.8 40℃ + 219.482
P = 59.16 mmHg Vapor Pressure for Water
1750.286 40℃ + 235 = 59.16 mmHg
log (P ) = 6.95464 − P Vapor Pressure for Mixture
0.854755.33mmHg + 0.145359.16mmHg = 55.89mmHg Mole of Water
g 0.2ml1 ml = 0.011mole g 18 mol Mole of Toluene
g 0.2ml0.87 ml = 0.0019mole g 92.14 mol Mole fraction of water
0.011mole = 0.85 0.011mole + 0.0019mole Mole fraction of Toluene
0.0019mole = 0.15 0.011mole + 0.0019mole Volume Percentage of Water
0.2 x 100% = 8.00% 0.2 + 2.3 Volume Percentage of Toluene
2.3 x 100% = 92.0% 0.2 + 2.3
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